A problem in the area of air care devices is the uncontrolled “distillation” of fragrance components of differing volatilities, resulting in a variable fragrance profile over time, as perceived by the consumer. The use of carriers or solvents in fragrances aids in the uniform distribution or evaporation of these fragrance components and leads to a more homogeneous fragrance profile.
Many materials are used as carriers in air care devices including glycol ethers, isoparaffinic solvents (e.g., Isopar® solvents commercially available from ExxonMobil) and various branched esters. One problem associated with these materials is that many are classified as VOCs (volatile organic compounds). VOC's are increasingly of environmental and regulatory concern. There is one class of VOCs, low vapor pressure VOC's (LVPVOCs), that are not as harmful to the atmosphere and are generally allowed under even the most stringent environmental regulations. This class of VOC has lower vapor pressure than regular VOCs as defined by standard definitions (e.g., <0.1 mm Hg at 20° C.).
U.S. Published Application No. 2008/0308648 discloses, in the generic sense, fragrance compositions containing Dowanol DPMA for use in a non-electric, wick-type device. DPMA has not, heretofor, been widely used as a fragrance carrier in liquid electrical air freshener devices, if used at all. The low volatility of low vapor pressure VOCs, such as DPMA, presents unique challenges. The decreased vapor pressure changes the compositions' perceived fragrance profile, as compared to the same fragrance composition used with a high vapor pressure VOC solvent (HVPVOC solvent).
There is a need for hedonically pleasing fragrance compositions that can be combined with low vapor pressure VOC solvents, such as dipropylene glycol methyl ether acetate. For example, there is a need for fragrance compositions that can be combined with a low vapor pressure VOC carrier for use in a liquid electrical air freshener, such as a heated wick delivery system, a piezoelectrical spraying system, an electrospray device or a Venturi device. It is desired to provide fragrance compositions suitable for use in air fresheners that avoid the regulatory problems associated with many of the glycol ether compounds commonly found in liquid electrical air fresheners. It is also desired to provide compositions that include a low pressure VOC (e.g., DPMA) and a fragrance composition wherein the evaporation rate is regulated to within a predetermined period of time (e.g., 30 days, or 40 days, or 60 days), during which at least substantially all of the fragrance is effectively evaporated into the surrounding environment, preferably in a controlled fashion.
It is thus an object to provide compositions that include one or more low pressure VOC (e.g., DPMA) and one or more a fragrance components that are economical to produce and have good safety characteristics, including low toxicity and low flammability.
Another and related object of the invention is to provide fragrance compositions that include a low pressure VOC (e.g., DPMA) and a fragrance composition having a controllable evaporation rate and that are suitable for use in, for example, a wick type air fragrance dispenser (air freshener). More specifically, it is an object of the invention to provide a controllable evaporation rate and permit effective utilization of the fragrance in a liquid electrical air freshener dispenser.